During a fortnight’s holiday in September, I experienced a fault in our Ducato-based motorhome that led to limited power and the EML (engine management light) coming on.
I have several diagnostic fault code readers in the workshop (they’re a good item to have in any motorhome tool kit), but ridiculously didn’t have one with me, so a quick detour to a parts shop got me a cheap and cheerful code reader, which enabled me to clear the code, but not before I had made a note of it. In fact there were two codes: P0238 and P2563.
The ‘P’ prefix tells us its a powertrain fault and 0238 is a turbo boost pressure that is out of range – too high. The 2563 denotes turbo boost control position sensor-signal out of range.
Now, in the old days, turbo boost pressure was controlled with a wastegate, which simply opened when the set pressure was reached to divert exhaust gases away from the turbo and so limit the boost. Modern systems use variable vane geometry to control boost pressures and the vane geometry is controlled via a solenoid mounted on the turbo.
If the vane geometry doesn’t work fully it can lead to an overboost situation which can be seriously harmful to the engine and will result in the 0238 code, triggering reduced power to prevent engine damage.
The fault occurred again later in the holiday when I hit resume on the cruise control at the bottom of a steep hill, so it wasn’t just a random one-off issue. If it had just been a boost pressure fault I’d have suspected the manifold absolute pressure (MAP) sensor, but with the variable vane fault coming up as well, it is more likely to be a problem on the turbo itself.
It’s easy to think these faults occur because of the complexity of modern engines and all the electronic sensors and controls involved, but there is another factor that often gets overlooked: the fact that it’s a motorhome means it probably gets driven relatively gently.
Bear in mind that the Ducato is first and foremost a delivery van, and white van man will often treat the accelerator as a switch – it’s on or off. Add to that the fact that most delivery vans will do in excess of 75,000 miles a year, while most motorhomes rarely achieve a tenth of that annual mileage, meaning they sit around for long periods of time doing nothing.
Now the turbo on Ducatos is tucked away, down the back of the engine, and an absolute pig to get to, so I opted to do a ‘relearn’ of the variable vane geometry travel, which so far seems to have worked.
If you’re thinking of embarking on a tour during the colder months, take a look at Motorhome Matt’s tips on how to prepare yourself and your motorhome for winter touring.
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